Pride doesn't come from nothing. Lucifer didn't just get prideful from nowhere, the most beautiful angel, high ranked with good authority from God, does not get prideful out of nowhere. He had to have taken his eyes of God, be distracted from his responsibility to have time to be prideful. Similarly, pride doesn't come suddenly, it comes when we are no longer focused on what we ought to be doing, when we are distracted with the authority rather than focused on the responsibility.